珠江水系广西江段鱼类多样性空间分布特征

研究对珠江水系广西江段15个站位的鱼类群落展开了调查, 共采集渔获物67985尾, 隶属于23科134种, 鲤形目种类(92种)最多, 占总数69%。采集到外来生物11种, 其中, 罗非鱼几乎遍布整个广西水域, 说明广西江段外来水生生物入侵严重。各江段以小型鱼类居多, 鱼类小型化严重。空间分布呈现一级河流物种多样性指数高, 均匀度高; 二级河流多样性指数低, 均匀度低的趋势。特别是经过十级水电开发后的红水河江段, 渔业资源量最低, 鱼类群落结构与其他江段具有显著的差异(P<0.05)。研究结果是珠江水系自然渔业资源长期调查的一部分, 将对广西渔业资源多样性的保护管理和可持续利用提供科学依据。

FISH DIVERSITY AND DISTRIBUTION PATTERN OF THE PEARL RIVER SYSTEM IN GUANGXI

Guangxi Province is located in the southern China and the upper and middle reaches of the Pearl River. It spans north tropical, south subtropical and central subtropical regions. The diversity of habitats in these regions promotes high fish species diversity. However, considering the reduction of global fishery resources due to numerous anthropogenic stressors, especially the over-construction of dams, studies on the spatial distribution of fish communities are limited and urgently needed. This study investigated fish diversity and distribution patterns of the Pearl River in Guangxi based on an investigation of 15 sample sites. A total of 67985 individual fishes were collected during the study period, including 134 taxa representing 23 families. The Cypriniformes order, representing 92 taxa, accounted for 69% of the total fish collected. A total of 11 non-native species were collected, of which tilapia was the highest abundant, almost all over the Guangxi. This suggests that the invasion of non-native species is serious in the Pearl River in Guangxi, and fish miniaturization is also serious. Significantly higher species diversity and evenness were recorded in the first order streams, and low species diversity and low evenness were recorded in the second order streams. The spatial variation in fish assemblages were significantly different in different river sections (P<0.05), such as the Hongshuihe River section with the lowest fishery resources. A comparison with historical data revealed that fish species have decreased sharply and the spatial distribution of fish communities has changed significantly. The present study is part of a long-term investigation of the Pearl River’s wild fishery resources. Therefore, understanding processes outlined in this study will help protect the diversity of fish communities, which is critical to the sustainability of fish diversity of the Pearl River in Guangxi Province.